Novel SrCo 1− yNb yO 3− δ cathodes for intermediate-temperature solid oxide fuel cells

Abstract

Perovskite oxides SrCo 1− y Nb y O 3− δ (SCN y, y = 0.00–0.20) are investigated as potential cathode materials for intermediate-temperature solid oxide fuel cells (IT-SOFCs) on La 0.9Sr 0.1Ga 0.8Mg 0.2O 3− δ (LSGM) electrolyte. Compared to the undoped SrCoO 3− δ , the Nb doping significantly improves the thermal stability and enhances the electrical conductivity of the SCN y oxides. The cubic phase of the SCN y oxides with high thermal stability can be totally obtained when the Nb doping content y ≥ 0.10. Among the investigated compositions, the SrCo 0.9Nb 0.1O 3− δ oxide exhibits the highest electrical conductivity of 461–145 S cm −1 over the temperature range of 300–800 °C in air. The SCN y cathode has a good chemical compatibility with the LSGM electrolyte for temperatures up to 1050 °C for 5 h. The area specific resistances of SCN y with y = 0.10, 0.15 and 0.20 cathodes on LSGM electrolyte are 0.083, 0.099 and 0.110 Ω cm 2 at 700 °C, respectively. At y = 0.10, 0.15 and 0.20, the maximum power densities of a single-cell with SCN y cathodes on 300-μm thick LSGM electrolyte achieve 675, 642 and 625 mW cm −2 at 800 °C, respectively. These results indicate that SCN y perovskite oxides with cubic phase are potential cathode materials for application in IT-SOFCs.